This invention relates to a stabilizing plate, used in a magnetic disk recording and reproduction device for recording and reproduction with a flexible magnetic disk, to maintain a good contact of a magnetic head against the magnetic disk.
In a recording and reproduction device which uses a thin, flexible magnetic disk as a recording medium, when the magnetic head is simply caused to come in contact against the magnetic disk, the magnetic disk tends to be deformed by the pressure of the magnetic head and to come away from the magnetic head, and a stable contact is not obtained.
Heretofore, there has been an attempt in which a magnetic disk control member (hereinafter simply referred to as "control member") is provided in the vicinity of the magnetic head to generate a negative pressure between the control member and the magnetic disk. The negative pressure attracts the magnetic disk towards the magnetic head side and the magnetic disk is pressed against the magnetic head to obtain a stable head contact.
Referring to FIG. 7, control members 13 are disposed at the upstream side and the downstream side of a magnetic head 11 with respect to the rotational direction (arrow R) of a magnetic disk 12. The surfaces of the control members opposing the magnetic disk 12 are formed to be inclined so that the surfaces become more distant from a free rotary surface plane N of the magnetic disk 12 towards the downstream side with respect to the rotational direction of the magnetic disk. Thus, as the magnetic disk 12 rotates at a high speed, a negative pressure is generated between the inclined surfaces and the magnetic disk.
In this specification, the term "free rotary surface plane" is defined as a rotary surface plane of a magnetic disk attached to a spindle motor of the magnetic disk recording and reproduction device, rotating with no action of external forces.
However, since, in the prior art control members 13, the surfaces opposing the magnetic disk 12 become more distant from the free rotary surface plane N of the magnetic disk 12 towards the downstream side with respect to the rotational direction of the magnetic disk, when the magnetic disk 12 is deflected along the control members 13, the amount of deflection (indicated by l in FIG. 7) tends to become excessive at the downstream side. As a result, the surface of the magnetic disk 12 tends to vibrate to a great extent in association with the high-speed rotation of the magnetic disk 12, which can deteriorate stable sliding contact with the magnetic head 11.
Furthermore, since the deflection of the magnetic disk 12 is asymmetric with respect to the magnetic head 11 between the upstream side and the downstream side, the front end of the magnetic head 11 must be inclined by 2.degree.-4.degree. towards the upstream side with respect to the rotational direction of the magnetic disk in order to obtain a sufficient head contact. Setting of the inclination of the magnetic head 11 requires a very complicated procedure.
When the magnetic disk 12 begins to rotate, the magnetic disk is normally located on its free rotary surface plane N with a large spacing between the magnetic disk 12 and the control members 13, and the control members 13 are required to generate a negative pressure sufficient to attract the magnetic disk 12. On the other hand, during the steady-state rotation of the magnetic disk 12 after it is attracted towards the control member 13 side, the amount of negative pressure is not required to be as large as that required when the magnetic disk 12 is first started. However, with the prior art control members 13, when the magnetic disk 12 is attracted and the distance between the magnetic disk 12 and the control members 13 becomes small, a greater amount of negative pressure is generated on the inclined surfaces which, conjointly with the above-described excessive deformation of the magnetic disk 12, results in an increase in the rotational driving torque of the magnetic disk 12.